Feeling Very Self-Conscious

I'm a 23 year old female. I weigh 86 pounds and am 5'4. According to those stats, my BMI is considered severely underweight. However, I feel like a pile of flub. My legs jiggle when I walk and I CAN'T STAND IT. I can also pinch more on my abdominal area then I used to be able to, even though I've been at this weight and height for over 4 years. I blame it on my job that I've been at for nearly a year now--sedentary desk job 9-5. (I used to be a waitress when I was in college--much different than this).

I work out 5 nights a week which includes a 30 min work out DVD (usually weight lifting, Jillian Michaels Yoga Burn, or pilates) and a 2 mile brisk walk. I want to feel better about myself but I'm not sure what to do. I know I shouldn't eat less than what I currently do (approximately 1800 calories a day). I also eat very healthfully (no fried foods, lots of veggies and fruit, lean protein, whole grains and low fat dairy). I have maybe 2-3 glasses of wine a week. I don't snack.

My goal is to become more healthy and fit... or really just to feel better about myself. Am I doing something wrong? If so, what and how do I fix it? I'm fine with the number on the scale going up--that's not an issue (I'm not anorexic nor have I ever had any form of eating disorder). The issue is not feeling tone enough. I'd love to gain lean muscle, I just don't know how--my current routine doesn't seem to be doing anything to help.

Any advice or words of encouragement would be greatly appreciated. Please don't criticize me.. I do enough of that to myself.

1) Snack and eat more! The reason you are so underweight but still look a little soft is that you don't have much muscle, and you can't build muscle without eating. Steer clear of junk food, but eat more.

2) You may need to modify your exercise routine. If you're sweating, you are burning calories. But to build muscle, you must feel a burn in the muscles that you are using. If you feel a little sore the next day, all the better. (If you have real pain, stop.).

Walking doesn't really build much muscle. If you live near hills, try hill walking. Biking and stair climbing are good ways to build muscle. So are squats or leg lifts, and you don't need any equipment at all to do those. If leg lifts are too easy, put on some heavier shoes and do more of them.

Building the upper body, it's really all about the weights. But if you've been doing the same routine with the same weights for more than a few weeks, it's time to step it up. Aim for the burn, that's when you know you've done it right.

At 5'4" and 86 pounds, you do not weigh enough to have lean muscle.
Your body has digested all your muscle in an effort to stay alive, and will continue to do so until you start eating more and gaining weight. Until then, you will remain flabby. The "flab" is skin, hanging off bones, with no muscle underneath to support it.

You say you do not have an eating disorder. I did, in my 20s. I am also 5'4". At the height of my eating disorder, I weighed 93 pounds, which is seven pounds more than you currently do.
I was a skeletal wraith. I believed I was fat.

I suggest you see a doctor.
I am not trying to be hurtful, I'm trying to save your life.
Exercise is not what you need. You don't weigh enough to develop muscle or "tone up". All exercise is going to do is burn more calories, calories you can't afford to burn at this point, because you need them to maintain your basic bodily functions- your brain and heart functions.